What are the methods for pre-selection of tungsten ore?

1. Manual picking

Manual sorting is a simple mineral processing method in which on-site operators sort the ores based on differences in surface characteristics such as color and texture. It has a good pre-selection effect on ores with a particle size of 18-200mm. The color difference between quartz vein type wolframite and waste rock is obvious, so the manual selection method has been widely used. The waste rate of manual picking can reach 40% to 60%, and the mineral processing cost is low, but there are also shortcomings such as low sorting efficiency.

2. Pre-selection by re-selection method

 At present, the most industrially valuable tungsten ores are scheelite and wolframite. The pure mineral density of wolframite is 7.2-7.5 g/cm3 and the WO3 content is 76%. The pure mineral density of scheelite is 5.8-6.2 g/cm3. , WO3 content is 80.6%, and has the characteristics of density significantly higher than that of surrounding rock and gangue, so the gravity separation method can be used for pre-selection and separation. Currently, the gravity separation methods that can be applied to tungsten ore pre-selection include heavy media pre-selection, vibrating screen jig pre-selection, spiral concentrator and centrifugal concentrator pre-selection.

3. Pre-selection by magnetic separation method

Magnetic separation is a mineral separation method that uses the magnetic differences of minerals to achieve separation. Wolframite has weak magnetism and can be separated from non-magnetic minerals using strong magnetic separation. And scheelite is often associated with other metallic minerals. When these metallic minerals are also magnetic, the magnetic separation method can also be used to pre-select and discard scheelite.

4. Intelligent photoelectric pre-selection

Intelligent photoelectric pre-selection uses various light signals to perform line scanning on bulk materials, and uses sensors or a combination of different sensors to detect the bulk materials particle by particle. According to the sensor detection results and data processing results, the mechanically rejected parts do not meet the requirements in terms of composition. Requires particle sorting technology. Intelligent photoelectric pre-selection technology has been widely researched and applied in the field of tungsten ore pre-selection, mainly including image color sorting technology and XRT pre-selection technology.